I had three rounds of interviews with Google within one month.

I received the information one month before the interviews, so I found some open judge websites to solve algorithm problems that I might encounter during the interviews.

We conducted the interview through Google Hangouts and coded in a Google Doc. In the first round of the interview, the interviewer asked me: given a set of points in the plane, output all the points which are collinear.

Given an array of numbers, output the array like this: a1 <= a2 >= a3 <= a4 >= a5...